script: Abstract HTMLLinkElement and StyleElement into StylesheetOwner.

components/script/dom/element.rs

@@ -51,9 +51,11 @@ use dom::htmlimageelement::{HTMLImageElement, LayoutHTMLImageElementHelpers};
 use dom::htmlinputelement::{HTMLInputElement, LayoutHTMLInputElementHelpers};
 use dom::htmllabelelement::HTMLLabelElement;
 use dom::htmllegendelement::HTMLLegendElement;
+use dom::htmllinkelement::HTMLLinkElement;
 use dom::htmlobjectelement::HTMLObjectElement;
 use dom::htmloptgroupelement::HTMLOptGroupElement;
 use dom::htmlselectelement::HTMLSelectElement;
+use dom::htmlstyleelement::HTMLStyleElement;
 use dom::htmltablecellelement::{HTMLTableCellElement, HTMLTableCellElementLayoutHelpers};
 use dom::htmltableelement::{HTMLTableElement, HTMLTableElementLayoutHelpers};
 use dom::htmltablerowelement::{HTMLTableRowElement, HTMLTableRowElementLayoutHelpers};
@@ -109,6 +111,7 @@ use style::sink::Push;
 use style::stylist::ApplicableDeclarationBlock;
 use style::values::CSSFloat;
 use style::values::specified::{self, CSSColor, CSSRGBA, LengthOrPercentage};
+use stylesheet_loader::StylesheetOwner;
 
 // TODO: Update focus state when the top-level browsing context gains or loses system focus,
 // and when the element enters or leaves a browsing context container.
@@ -2407,6 +2410,18 @@ impl Element {
         })
     }
 
+    pub fn as_stylesheet_owner(&self) -> Option<&StylesheetOwner> {
+        if let Some(s) = self.downcast::<HTMLStyleElement>() {
+            return Some(s as &StylesheetOwner)
+        }
+
+        if let Some(l) = self.downcast::<HTMLLinkElement>() {
+            return Some(l as &StylesheetOwner)
+        }
+
+        None
+    }
+
     // https://html.spec.whatwg.org/multipage/#category-submit
     pub fn as_maybe_validatable(&self) -> Option<&Validatable> {
         let element = match self.upcast::<Node>().type_id() {

components/script/dom/htmllinkelement.rs

@@ -5,6 +5,7 @@
 use cssparser::Parser as CssParser;
 use dom::attr::Attr;
 use dom::bindings::cell::DOMRefCell;
+use dom::bindings::codegen::Bindings::DOMTokenListBinding::DOMTokenListBinding::DOMTokenListMethods;
 use dom::bindings::codegen::Bindings::HTMLLinkElementBinding;
 use dom::bindings::codegen::Bindings::HTMLLinkElementBinding::HTMLLinkElementMethods;
 use dom::bindings::inheritance::Castable;
@@ -20,6 +21,7 @@ use dom::node::{Node, document_from_node, window_from_node};
 use dom::stylesheet::StyleSheet as DOMStyleSheet;
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
+use net_traits::ReferrerPolicy;
 use script_traits::{MozBrowserEvent, ScriptMsg as ConstellationMsg};
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
@@ -30,7 +32,7 @@ use style::attr::AttrValue;
 use style::media_queries::parse_media_query_list;
 use style::str::HTML_SPACE_CHARACTERS;
 use style::stylesheets::Stylesheet;
-use stylesheet_loader::{StylesheetLoader, StylesheetContextSource};
+use stylesheet_loader::{StylesheetLoader, StylesheetContextSource, StylesheetOwner};
 
 unsafe_no_jsmanaged_fields!(Stylesheet);
 
@@ -216,28 +218,6 @@ impl VirtualMethods for HTMLLinkElement {
 
 
 impl HTMLLinkElement {
-    pub fn increment_pending_loads_count(&self) {
-        self.pending_loads.set(self.pending_loads.get() + 1)
-    }
-
-    /// Returns None if there are still pending loads, or whether any load has
-    /// failed since the loads started.
-    pub fn load_finished(&self, succeeded: bool) -> Option<bool> {
-        assert!(self.pending_loads.get() > 0, "What finished?");
-        if !succeeded {
-            self.any_failed_load.set(true);
-        }
-
-        self.pending_loads.set(self.pending_loads.get() - 1);
-        if self.pending_loads.get() != 0 {
-            return None;
-        }
-
-        let any_failed = self.any_failed_load.get();
-        self.any_failed_load.set(false);
-        Some(any_failed)
-    }
-
     /// https://html.spec.whatwg.org/multipage/#concept-link-obtain
     fn handle_stylesheet_url(&self, href: &str) {
         let document = document_from_node(self);
@@ -297,6 +277,40 @@ impl HTMLLinkElement {
     }
 }
 
+impl StylesheetOwner for HTMLLinkElement {
+    fn increment_pending_loads_count(&self) {
+        self.pending_loads.set(self.pending_loads.get() + 1)
+    }
+
+    fn load_finished(&self, succeeded: bool) -> Option<bool> {
+        assert!(self.pending_loads.get() > 0, "What finished?");
+        if !succeeded {
+            self.any_failed_load.set(true);
+        }
+
+        self.pending_loads.set(self.pending_loads.get() - 1);
+        if self.pending_loads.get() != 0 {
+            return None;
+        }
+
+        let any_failed = self.any_failed_load.get();
+        self.any_failed_load.set(false);
+        Some(any_failed)
+    }
+
+    fn parser_inserted(&self) -> bool {
+        self.parser_inserted.get()
+    }
+
+    fn referrer_policy(&self) -> Option<ReferrerPolicy> {
+        if self.RelList().Contains("noreferrer".into()) {
+            return Some(ReferrerPolicy::NoReferrer)
+        }
+
+        None
+    }
+}
+
 impl HTMLLinkElementMethods for HTMLLinkElement {
     // https://html.spec.whatwg.org/multipage/#dom-link-href
     make_url_getter!(Href, "href");

components/script/dom/htmlstyleelement.rs

@@ -19,13 +19,14 @@ use dom::node::{ChildrenMutation, Node, document_from_node, window_from_node};
 use dom::stylesheet::StyleSheet as DOMStyleSheet;
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
+use net_traits::ReferrerPolicy;
 use script_layout_interface::message::Msg;
 use std::cell::Cell;
 use std::sync::Arc;
 use style::media_queries::parse_media_query_list;
 use style::parser::ParserContextExtraData;
 use style::stylesheets::{Stylesheet, Origin};
-use stylesheet_loader::StylesheetLoader;
+use stylesheet_loader::{StylesheetLoader, StylesheetOwner};
 
 #[dom_struct]
 pub struct HTMLStyleElement {
@@ -64,28 +65,6 @@ impl HTMLStyleElement {
                            HTMLStyleElementBinding::Wrap)
     }
 
-    pub fn increment_pending_loads_count(&self) {
-        self.pending_loads.set(self.pending_loads.get() + 1)
-    }
-
-    /// Returns None if there are still pending loads, or whether any load has
-    /// failed since the loads started.
-    pub fn load_finished(&self, succeeded: bool) -> Option<bool> {
-        assert!(self.pending_loads.get() > 0, "What finished?");
-        if !succeeded {
-            self.any_failed_load.set(true);
-        }
-
-        self.pending_loads.set(self.pending_loads.get() - 1);
-        if self.pending_loads.get() != 0 {
-            return None;
-        }
-
-        let any_failed = self.any_failed_load.get();
-        self.any_failed_load.set(false);
-        Some(any_failed)
-    }
-
     pub fn parse_own_css(&self) {
         let node = self.upcast::<Node>();
         let element = self.upcast::<Element>();
@@ -137,10 +116,6 @@ impl HTMLStyleElement {
             })
         })
     }
-
-    pub fn parser_inserted(&self) -> bool {
-        self.parser_inserted.get()
-    }
 }
 
 impl VirtualMethods for HTMLStyleElement {
@@ -168,6 +143,37 @@ impl VirtualMethods for HTMLStyleElement {
     }
 }
 
+impl StylesheetOwner for HTMLStyleElement {
+    fn increment_pending_loads_count(&self) {
+        self.pending_loads.set(self.pending_loads.get() + 1)
+    }
+
+    fn load_finished(&self, succeeded: bool) -> Option<bool> {
+        assert!(self.pending_loads.get() > 0, "What finished?");
+        if !succeeded {
+            self.any_failed_load.set(true);
+        }
+
+        self.pending_loads.set(self.pending_loads.get() - 1);
+        if self.pending_loads.get() != 0 {
+            return None;
+        }
+
+        let any_failed = self.any_failed_load.get();
+        self.any_failed_load.set(false);
+        Some(any_failed)
+    }
+
+    fn parser_inserted(&self) -> bool {
+        self.parser_inserted.get()
+    }
+
+    fn referrer_policy(&self) -> Option<ReferrerPolicy> {
+        None
+    }
+}
+
+
 impl HTMLStyleElementMethods for HTMLStyleElement {
     // https://drafts.csswg.org/cssom/#dom-linkstyle-sheet
     fn GetSheet(&self) -> Option<Root<DOMStyleSheet>> {

components/script/stylesheet_loader.rs

@@ -3,15 +3,13 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use document_loader::LoadType;
-use dom::bindings::codegen::Bindings::DOMTokenListBinding::DOMTokenListBinding::DOMTokenListMethods;
-use dom::bindings::codegen::Bindings::HTMLLinkElementBinding::HTMLLinkElementBinding::HTMLLinkElementMethods;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::DomObject;
+use dom::element::Element;
 use dom::eventtarget::EventTarget;
 use dom::htmlelement::HTMLElement;
 use dom::htmllinkelement::HTMLLinkElement;
-use dom::htmlstyleelement::HTMLStyleElement;
 use dom::node::{document_from_node, window_from_node};
 use encoding::EncodingRef;
 use encoding::all::UTF_8;
@@ -33,6 +31,23 @@ use style::parser::ParserContextExtraData;
 use style::stylesheets::{ImportRule, Stylesheet, Origin};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 
+pub trait StylesheetOwner {
+    /// Returns whether this element was inserted by the parser (i.e., it should
+    /// trigger a document-load-blocking load).
+    fn parser_inserted(&self) -> bool;
+
+    /// Which referrer policy should loads triggered by this owner follow, or
+    /// `None` for the default.
+    fn referrer_policy(&self) -> Option<ReferrerPolicy>;
+
+    /// Notes that a new load is pending to finish.
+    fn increment_pending_loads_count(&self);
+
+    /// Returns None if there are still pending loads, or whether any load has
+    /// failed since the loads started.
+    fn load_finished(&self, successful: bool) -> Option<bool>;
+}
+
 pub enum StylesheetContextSource {
     // NB: `media` is just an option so we avoid cloning it.
     LinkElement { media: Option<MediaList>, url: ServoUrl },
@@ -146,35 +161,18 @@ impl FetchResponseListener for StylesheetContext {
             successful = metadata.status.map_or(false, |(code, _)| code == 200);
         }
 
-        if let Some(ref link) = elem.downcast::<HTMLLinkElement>() {
-            if link.parser_inserted() {
+        let owner = elem.upcast::<Element>().as_stylesheet_owner()
+            .expect("Stylesheet not loaded by <style> or <link> element!");
+        if owner.parser_inserted() {
             document.decrement_script_blocking_stylesheet_count();
         }
-        } else if let Some(ref style) = elem.downcast::<HTMLStyleElement>() {
-            if style.parser_inserted() {
-                document.decrement_script_blocking_stylesheet_count();
-            }
-        } else {
-            unreachable!(
-                "Stylesheet loads can only be triggered by <link> or <style> elements!");
-        }
 
         let url = self.source.url();
         document.finish_load(LoadType::Stylesheet(url));
 
-        if let Some(ref link) = elem.downcast::<HTMLLinkElement>() {
-            if let Some(any_failed) = link.load_finished(successful) {
+        if let Some(any_failed) = owner.load_finished(successful) {
             let event = if any_failed { atom!("error") } else { atom!("load") };
-                link.upcast::<EventTarget>().fire_event(event);
-            }
-        } else if let Some(ref style) = elem.downcast::<HTMLStyleElement>() {
-            if let Some(any_failed) = style.load_finished(successful) {
-                let event = if any_failed { atom!("error") } else { atom!("load") };
-                style.upcast::<EventTarget>().fire_event(event);
-            }
-        } else {
-            unreachable!(
-                "Stylesheet loads can only be triggered by <link> or <style> elements!");
+            elem.upcast::<EventTarget>().fire_event(event);
         }
     }
 }
@@ -214,21 +212,14 @@ impl<'a> StylesheetLoader<'a> {
         });
 
 
-        let mut referrer_policy = document.get_referrer_policy();
-        if let Some(ref link) = self.elem.downcast::<HTMLLinkElement>() {
-            link.increment_pending_loads_count();
-            if link.parser_inserted() {
+        let owner = self.elem.upcast::<Element>().as_stylesheet_owner()
+            .expect("Stylesheet not loaded by <style> or <link> element!");
+        let referrer_policy = owner.referrer_policy()
+            .or_else(|| document.get_referrer_policy());
+        owner.increment_pending_loads_count();
+        if owner.parser_inserted() {
             document.increment_script_blocking_stylesheet_count();
         }
-            if link.RelList().Contains("noreferrer".into()) {
-                referrer_policy = Some(ReferrerPolicy::NoReferrer);
-            }
-        } else if let Some(ref style) = self.elem.downcast::<HTMLStyleElement>() {
-            style.increment_pending_loads_count();
-            if style.parser_inserted() {
-                document.increment_script_blocking_stylesheet_count();
-            }
-        }
 
         let request = RequestInit {
             url: url.clone(),